/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.pig.impl.plan;
import java.lang.StringBuilder;
import java.util.List;
import org.apache.pig.data.DataType;
import org.apache.pig.impl.util.MultiMap;
import org.apache.pig.impl.util.Pair;
/**
* A struct detailing how a projection is altered by an operator.
*/
public class ProjectionMap {
/**
* Quick way for an operator to note that its input and output are the same.
*/
private boolean mChanges = true;
/**
* Map of field changes, with keys being the output fields of the operator
* and values being the projection map columns. Fields are numbered from 0.
* So for a foreach operator derived from 'B = foreach A generate $0, $2,
* (int)$3, udf($1)' would produce a mapping of 0->(0, 0), 2->(0, 1),
* 3->[(0, 2), DataType.INTEGER]
*/
private MultiMap<Integer, Column> mMappedFields;
/**
* List of fields removed from the input. This includes fields that were
* transformed, and thus are no longer the same fields. Using the example
* foreach given under mappedFields, this list would contain '(0,1)'.
*/
private List<Pair<Integer, Integer>> mRemovedFields;
/**
* List of fields in the output of this operator that were created by this
* operator. Using the example foreach given under mappedFields, this list
* would contain '3'.
*/
private List<Integer> mAddedFields;
/**
*
* @param changes
* to indicate if this projection map changes its input or not
*/
public ProjectionMap(boolean changes) {
this(null, null, null, changes);
}
/**
*
* @param mapFields
* the mapping of input column to output column
* @param removedFields
* the list of input columns that are removed
* @param addedFields
* the list of columns that are added to the output
*/
public ProjectionMap(MultiMap<Integer, Column> mapFields,
List<Pair<Integer, Integer>> removedFields,
List<Integer> addedFields) {
this(mapFields, removedFields, addedFields, true);
}
/**
*
* @param mapFields
* the mapping of input column to output column
* @param removedFields
* the list of input columns that are removed
* @param addedFields
* the list of columns that are added to the output
* @param changes
* to indicate if this projection map changes its input or not
*/
private ProjectionMap(MultiMap<Integer, Column> mapFields,
List<Pair<Integer, Integer>> removedFields,
List<Integer> addedFields, boolean changes) {
mMappedFields = mapFields;
mAddedFields = addedFields;
mRemovedFields = removedFields;
mChanges = changes;
}
/**
*
* @return the mapping of input column to output column
*/
public MultiMap<Integer, Column> getMappedFields() {
return mMappedFields;
}
/**
*
* @param fields
* the mapping of input column to output column
*/
public void setMappedFields(MultiMap<Integer, Column> fields) {
mMappedFields = fields;
}
/**
*
* @return the list of input columns that are removed
*/
public List<Pair<Integer, Integer>> getRemovedFields() {
return mRemovedFields;
}
/**
*
* @param fields
* the list of input columns that are removed
*/
public void setRemovedFields(List<Pair<Integer, Integer>> fields) {
mRemovedFields = fields;
}
/**
*
* @return the list of columns that are added to the output
*/
public List<Integer> getAddedFields() {
return mAddedFields;
}
/**
*
* @param fields
* the list of columns that are added to the output
*/
public void setAddedFields(List<Integer> fields) {
mAddedFields = fields;
}
/**
*
* @return if this projection map changes its input or not
*/
public boolean changes() {
return getChanges();
}
/**
*
* @return if this projection map changes its input or not
*/
public boolean getChanges() {
return mChanges;
}
/**
*
* @param changes
* if this projection map changes its input or not
*/
public void setChanges(boolean changes) {
mChanges = changes;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("changes: " + mChanges);
sb.append(" mapped fields: " + mMappedFields);
sb.append(" added fields: " + mAddedFields);
sb.append(" removed fields: " + mRemovedFields);
return sb.toString();
}
/**
*
* A wrapper for projection map columns to contain the input number, input
* column. Additionally, if a cast is used, record the type of the cast
*
*/
public static class Column {
private Pair<Integer, Integer> mInputColumn;
private boolean mCast = false;
private byte mCastType = DataType.UNKNOWN;
/**
*
* @param inputColumn
* A pair of integers representing the input number and the
* input column number
*/
public Column(Pair<Integer, Integer> inputColumn) {
this(inputColumn, false, DataType.UNKNOWN);
}
/**
*
* @param inputColumn
* A pair of integers representing the input number and the
* input column number
* @param cast
* true if the input column has a cast
* @param castType
* the data type of the cast
*/
public Column(Pair<Integer, Integer> inputColumn, boolean cast,
byte castType) {
mInputColumn = inputColumn;
mCast = cast;
mCastType = castType;
}
/**
*
* Get the mapped column details
*
* @return A pair of integers representing the input number and the
* input column number
*/
public Pair<Integer, Integer> getInputColumn() {
return mInputColumn;
}
/**
*
* Check if the column is cast
*
* @return true if the input column has a cast; false otherwise
*/
public boolean getCast() {
return mCast;
}
/**
*
* Check if the column is cast
*
* @return true if the input column has a cast; false otherwise
*/
public boolean cast() {
return getCast();
}
/**
*
* Get the data type of the cast
*
* @return the data type of the cast
*/
public byte getCastType() {
return mCastType;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append(mInputColumn);
if (mCast) {
sb.append(" cast to: " + DataType.findTypeName(mCastType));
}
return sb.toString();
}
}
}